IIRC it can give a 30% to 40% performance boost on APU based systems, as the increased bandwidth to the GPU allows for much faster processing. Alternatively, Intel decided to put a few hundred megs of cache on their iGPU, which has made their graphics performance much better, and lessened the gains from increased Ram speed.
https://semiaccurate.com/2014/01/15/exploring-effect-memory-...